Mechanical Thrombectomy of M2-Occlusion

Mechanical Thrombectomy for Treatment of Acute Cerebral Infarction due to Distal Medium Vessel Occlusions: A Retrospective Cohort Study

BACKGROUND

Mechanical thrombectomy (MT) is standard of care for acute cerebral infarction (ACI) due to large vessel occlusions. However, its clinical efficacy in patients with ACI due to distal medium vessel occlusions (DMVOs) remains unclear. This study evaluates the efficacy and safety of MT in patients with ACI due to DMVOs.

METHODS

Totally, 306 patients with ACI at a very early stage were assigned into DMVOs-MT, M1-MT, and DMVOs-intravenous thrombolysis (IVT) groups. These groups were compared regarding baseline data, recanalization rate, location of vessel occlusions, number of thrombectomy, first-pass recanalization, mRS scores, NIHSS scores, 90-day mRS scores, incidence of adverse events, and mortality. Risk factors for poor prognosis of patients with DMVOs following MT were analyzed.

RESULTS

DMVOs-MT and M1-MT groups showed comparable first-pass recanalization rates, recanalization rates, and NIHSS score reduction ratios, with marked differences in location of vessel occlusions. Versus DMVOs-IVT, DMVOs-MT had increased differences between pre- and post-treatment NIHSS scores and between pre-treatment NIHSS scores and NIHSS scores at discharge and elevated NIHSS reduction ratios. The poor prognosis rate of DMVOs-MT group was insignificantly different from that of M1-MT group but lower than that of DMVOs-IVT group. Adverse events and mortality incidences were comparable among the three groups. Diabetes, first-pass recanalization, and pre-treatment NIHSS scores were independent risk factors for poor prognosis in DMVO patients after MT.

CONCLUSION

MT is as effective and safe in patients with DMVOs as in patients with M1 occlusions. In patients with DMVOs, MT has higher efficacy and safety than IVT.

Clinical significance and prevalence of subarachnoid hyperdensities on flat detector CT after mechanical thrombectomy: does it really matter?

BACKGROUND

Subarachnoid hyperdensities after mechanical thrombectomy (MT) are a common finding. However, it is often regarded as clinically insignificant.

OBJECTIVE

With this single-center investigation, to identify the prevalence of subarachnoid hyperdensities following MT, associated predictors, and the impact on the clinical outcome of the patients.

METHODS

383 patients from the stroke registry were analyzed for the presence of subarachnoid hyperdensities on flat detector CT (FDCT) directly after the completion of MT, and on follow-up dual-energy CT, then classified according to a visual grading scale. 178 patients were included with anterior circulation occlusions. Regression analysis was performed to identify significant predictors, and Kruskal-Wallis analysis and Χ2 test were performed to test the variables among the different groups. The primary outcome was the modified Rankin Scale (mRS) score at 90 days and was analyzed with the Wilcoxon-Mann-Whitney rank-sum test.

RESULTS

The prevalence of subarachnoid hyperdensities on FDCT was (66/178, 37.1%) with patients experiencing a significant unfavorable outcome (P=0.035). Significantly fewer patients with subarachnoid hyperdensities achieved a mRS score of ≤3 at 90 days 25/66 (37.9%) vs 60/112 (53.6%), P=0.043). In addition, mortality was significantly higher in the subarachnoid hyperdensities group (34.8% vs 19.6%, P=0.024). Distal occlusions and a higher number of device passes were significantly associated with subarachnoid hyperdensities (P=0.026) and (P=0.001), respectively. Patients who received intravenous tissue plasminogen activator had significantly fewer subarachnoid hyperdensities (P=0.029).

CONCLUSIONS

Postinterventional subarachnoid hyperdensities are a frequent finding after MT and are associated with neurological decline and worse functional outcome. They are more common with distal occlusions and multiple device passes.

Hypoperfusion Intensity Ratio as an Indirect Imaging Surrogate in Patients With Anterior Circulation Large-Vessel Occlusion and Association of Baseline Characteristics With Poor Collateral Status

BACKGROUND

Collateral status (CS) plays a crucial role in infarct growth rate, risk of postthrombectomy hemorrhage, and overall clinical outcomes in patients with acute ischemic stroke (AIS) secondary to anterior circulation large-vessel occlusions (LVOs). Hypoperfusion intensity ratio has been previously validated as an indirect noninvasive pretreatment imaging biomarker of CS. In addition to imaging, derangements in admission laboratory findings can also influence outcomes in patients with AIS-LVO. Therefore, our study aims to assess the relationship between admission laboratory findings, baseline characteristics, and CS, as assessed by hypoperfusion intensity ratio in patients with AIS-LVO.

METHODS AND RESULTS

In this retrospective study, consecutive patients presenting with AIS secondary to anterior circulation LVO who underwent pretreatment computed tomography perfusion were included. The computed tomography perfusion data processed by RAPID (Ischema View, Menlo Park, CA) generated the hypoperfusion intensity ratio. Binary logistic regression models were used to assess the relationship between patients' baseline characteristics, admission laboratory findings, and poor CS. A total of 221 consecutive patients with AIS-LVO between January 2017 and September 2022 were included in our study (mean±SD age, 67.0±15.8 years; 119 men [53.8%]). Multivariable logistic regression showed that patients with AIS caused by cardioembolic and cryptogenic causes (adjusted odds ratio [OR], 2.67; 95% CI, 1.20-5.97; P=0.016), those who presented with admission National Institutes of Health Stroke Scale score ≥12 (adjusted OR, 3.12; 95% CI, 1.61-6.04; P=0.001), and male patients (adjusted OR, 2.06; 95% CI, 1.13-3.77; P=0.018) were associated with poor CS.

CONCLUSIONS

Stroke caused by cardioembolic or cryptogenic causes, admission National Institutes of Health Stroke Scale score of ≥12, and male sex were associated with poor CS, as defined by hypoperfusion intensity ratio in the patients with AIS-LVO.

Multicenter investigation of technical and clinical outcomes after thrombectomy for Proximal Medium Vessel Occlusion (pMeVO) by frontline technique

BACKGROUND

Endovascular thrombectomy(EVT) is the standard of care for large vessel occlusion(LVO) stroke. Data on technical and clinical outcome in proximal medium vessel occlusions(pMeVOs) comparing frontline techniques remain limited.

METHODS

We report an international multicenter retrospective study of patients undergoing EVT for stroke at 32 centers between 2015-2021. Patients were divided into LVOs(ICA/M1/Vertebrobasilar) or pMeVOs(M2/A1/P1) and categorized by thrombectomy technique. Primary outcome was 90-day good functional outcome(mRS ≤ 2). Multivariate logistic regressions were used to evaluate the impact of technical variables on clinical outcomes. Propensity score matching was used to compare outcome in patients with pMeVO treated with aspiration versus stent-retriever.

RESULTS

In the cohort of 5977 LVO and 1287 pMeVO patients, pMeVO did not independently predict good-outcome(p  =  0.55). In pMeVO patients, successful recanalization irrespective of frontline technique(aOR = 3.2,p < 0.05), procedure time ≤ 1-h(aOR = 2.2,p < 0.05), and thrombectomy attempts ≤ 4(aOR =  2.8,p < 0.05) were independent predictors of good-outcomes.In a propensity-matched cohort of aspiration versus stent-retriever pMeVO patients, there was no difference in good-outcomes. The rates of hemorrhage were higher(9%vs.4%,p < 0.01) and procedure time longer(51-min vs. 33-min,p < 0.01) with stent-retriever, while the number of attempts was higher with aspiration(2.5vs.2,p < 0.01). Rates of hemorrhage and good-outcome showed an exponential relationship to procedural metrics, and were more dependent on time in the aspiration group compared to attempts in the stent-retriever group.

CONCLUSIONS

Clinical outcomes following EVT for pMeVO are comparable to those in LVOs. The golden hour or 3-pass rules in LVO thrombectomy still apply to pMeVO thrombectomy. Different techniques may exhibit different futility metrics; SR thrombectomy was more influenced by attempts whereas aspiration was more dependent on procedure time.

Mechanical thrombectomy for middle cerebral artery M2 occlusions

BACKGROUND

The safety and efficacy of mechanical thrombectomy (MT) for proximal large vessel occlusion after acute ischemic stroke (AIS) have been demonstrated. Clinical investigations of endovascular approaches for treating AIS due to M2 occlusions have been ongoing.

PURPOSE

To assess the outcomes of M2 occlusions according to treatment modality and anatomical division.

METHODS

A total of 113 consecutive M2 occlusions treated with endovascular treatment (EVT) at our tertiary stroke center between January 2019 and December 2022 were retrospectively analyzed. Patients were divided into three groups: mechanical thrombectomy (MT); intravenous thrombolysis plus MT (IVT + MT); and IVT alone. The primary outcomes were good prognosis (mRS = 0-2) and mortality (mRS = 6) on day 90. The secondary outcome was to determine the differences in outcomes between lesions in the superior and inferior branches of M2.

RESULTS

In total, 55 (48.7%) patients underwent MT. In 42 (37.2%) patients, bridging IVT was performed with MT, and IVT alone was applied in 16 (14.2%) patients. Neither the prognosis at 90 days nor the mortality rate significantly differed among the groups. The outcomes did not significantly differ between occlusions in the superior and inferior branches of M2.

CONCLUSION

MT was found to be safe and effective for treating M2 occlusions in this series.

Aspiration thrombectomy of M2 segment in acute ischemic stroke: The clinical reality in a neurovascular reference center

OBJECTIVE

Our study aimed to evaluate safety, efficacy and clinical outcomes in patients with acute ischemic stroke with occlusion of M2 segment treated with thromboaspiration.

MATERIALS AND METHODS

A retrospective study was conducted in patients with ischemic stroke of M2 segment undergoing endovascular thromboaspiration. The time period analyzed was from October 2015 until February 2021. Thromboaspiration was performed with AXS Catalyst 5 (Stryker) or AXS Catalyst 6 (Stryker) catheters. The following parameters were assessed: risk factors for ischemic stroke, National Institutes of Health Stroke Scale (entry and discharge), pre-procedural fibrinolysis, pre-procedural and 24-h Alberta Stroke Program Early CT Score, recanalization time, number of passages for recanalization, Thrombolysis in cerebral infarction scale score, periprocedural complications, Modified Rankin Scale score at 90 days from procedure and mortality.

RESULTS

90 patients were included in the study. The mean age was 75 ± 11.1 with National Institutes of Health Stroke Scale at entry 13 ± 5 and 8 ± 4 at discharge. Pre-procedural fibrinolysis were performed in 40 patients. Pre-procedural Alberta Stroke Program Early CT Score were 8.8 ± 1.3 and 6.9 ± 2.4 after 24 h from the procedure. Time of recanalization from onset of symptoms was 300 ± 82 min. Number of passages for recanalization were 1.8 ± 1.1. Thrombolysis in cerebral infarction scale score ≥ 2b were obtained in 90 % of procedures. After 90 days 33 % of patient obtained an Modified Rankin Scale between 0 and 1 (between 0 and 2 was 40 %). We didn't detect any complication in 64 % of cases (subarachnoid haemorrhage in 2 %, HI1 and HI 2 in 15 %, PH1 in 9 % of patients, PH2 in 6 % of patients).

CONCLUSIONS

This paper confirms the usefulness and safety of thrombospiration in patients with ischemic stroke in the M2 segment with low intra-operative risks, high technical success and positive impact on the outcome of the patients.

Advances in mechanical thrombectomy for acute ischaemic stroke

Mechanical thrombectomy is a ground breaking treatment for acute ischaemic stroke caused by occlusion of a large vessel. Its efficacy over intravenous thrombolysis has been proven in multiple trials with a lower number needed to treat than percutaneous coronary intervention for acute myocardial infarction. However, access to this key treatment modality remains limited with a considerable postcode lottery across the UK and many parts of the world. The evidence base for mechanical thrombectomy dates back to 2015. Since then, there have been important advances in establishing and widening the criteria for treatment. This narrative review aims to summarise the current evidence base and latest advances for physicians and academics with an interest in recanalisation treatments for acute ischaemic stroke.

Aspiration thrombectomy of M2 middle cerebral artery occlusion to treat acute ischemic stroke: A core lab–adjudicated subset analysis from the COMPLETE registry and literature review

Background

Although the benefits of aspiration thrombectomy for treating acute ischemic stroke caused by proximal large vessel occlusion have been established, fewer data are available for evaluating aspiration thrombectomy of distal occlusion. The objective of this study was to evaluate, by means of prospectively collected data, the safety and efficacy of aspiration thrombectomy in patients with M2 middle cerebral artery (MCA) occlusion.

Methods

This study is a subset analysis of a global prospective multicenter observational registry that included patients who presented with either anterior or posterior large vessel occlusion and were eligible for mechanical thrombectomy using the Penumbra System including the Penumbra 3D Revascularization Device. For this analysis, all patients in the registry with M2 MCA occlusion were included.

Results

Of the 650 patients in the registry, 113 (17.4%) had M2 MCA occlusion. The rate of a modified treatment in cerebral infarction score of 2b to 3 after the procedure was 79.6% (90/113), the rate of a modified Rankin Scale score of 0–2 at 90 days was 72.5% (79/109), and the all-cause mortality rate at 90 days was 8.8% (10/113). Device-related serious adverse events occurred in one patient (0.9%) within 24 h and in two patients (1.8%) overall. Procedure-related serious adverse events occurred in four patients (3.5%) within 24 h and in six patients (5.3%) overall (nine events).

Conclusion

For appropriately selected patients, aspiration thrombectomy for acute ischemic stroke due to M2 MCA occlusion was safe and effective, with high rates of technical success and good functional outcome.

How to Define Fast and Slow Progressors in Any-Type Occlusion Acute Ischemic Stroke

The variable rate of infarct progression in acute ischemic stroke as assessed by various thresholds excludes a substantial proportion of patients due to time or core constraints. We evaluated 106 patients with any-type occlusion to compare these thresholds and assessed performance of hypoperfusion index (HI) for fast and slow rate of infarct progression. Seven (12.5%) were classified fast progressors and 23 (46%), 25 (50%), 12 (24%), and 33 (66%) slow progressors using different core and time criteria. In comparison, HI categorized 100% (n = 106) of cohort with optimal cutoff 0.5 for any-type occlusion (slow progressors: HI ≤ 0.5), sensitivity/specificity 100%/91%, AUC 0.94, and indicative of eligibility for reperfusion and clinical outcomes (median 90-day modified Rankin Scale; 2 for HI ≤ 0.5 versus 5). Estimation of progressors by HI seems comprehensive but needs external validation.

Safety and Efficacy of the Novel Low-Profile APERIO Hybrid17 for a Treatment of Proximal and Distal Vessel Occlusion in Acute Ischemic Stroke: A Multi-Center Experience

OBJECTIVE

To report our initial experience with the novel low-profile APERIO Hybrid17 Thrombectomy Device (AP17) for proximal and distal vessel occlusions in acute ischemic stroke.

METHODS

A multicentric retrospective analysis of patients treated with the AP17 was performed. The primary effectiveness endpoint was first-pass TICI ≥2b (Thrombolysis in cerebral infarction scale). The primary safety endpoint was the occurrence of hemorrhagic complications. Further outcome measures were number of passes, device-related complications, and 3-month functional outcome.

RESULTS

The AP17 was used in 71 patients (mean age: 73 years) with a median baseline National Institutes of Health Stroke Scale score of 9. Treated vessels were the carotid-T in 8 cases (11%), the M1-segment in 16 (23%), the M2-segment in 29 (41%), the anterior cerebral artery in 3 (4%), and basilar/posterior cerebral arteries in 15 (21%). The rates of first-pass and final TICI ≥2b were 75.6% and 92.7%, retrospectively, with a mean number of passes of 3 ± 2. Final TICI ≥2b rates were comparable between large and medium vessel occlusions. Symptomatic intracranial hemorrhages were recorded in 2 cases (2.8%). At 3-month clinical follow-up, a modified Rankin scale score ≤2 was achieved in 69.0% (29/42). The all-cause mortality at discharge was 17.4%.

CONCLUSIONS

The AP17 was associated with a reasonable safety and efficacy profile for both proximal and distal vessel occlusions. These results may contribute to establish mechanical thrombectomy for distal occlusions.

Endovascular treatment for acute ischaemic stroke due to medium vessel occlusion: data from ANGEL-ACT registry

OBJECTIVES

To investigate the safety and efficacy of endovascular treatment (EVT) for acute medium vessel occlusion (MeVO) in the anterior circulation and to explore the independent predictors of the 90-day good outcome for such patients.

METHODS

Data from ANGEL-ACT Registry were analysed in our study. The outcomes, such as the modified Rankin Scale (mRS) at 90 days, successful recanalisation rate and symptomatic intracranial haemorrhage (SICH) rate, were compared between MeVO and acute large vessel occlusions (LVO). Then, the independent predictors of the good outcome at 90 days in MeVO patients were determined by the logistic regression analyses.

RESULTS

We included 1032 subjects in the analysis, of which, 147 were MeVO and 885 were LVO. mRS at 90 days distribution (3 (0-4) vs 3 (0-5), common odds ratio (OR) =1.00, 95% confidence interval (CI) 0.73 to 1.38, p=0.994), SICH rate (4.8% vs 8.9%; OR=0.59, 95% CI 0.26 to 1.34, p=0.205) and successful recanalisation rate (89.8% vs 89.7%; OR=1.00 95% CI 0.51 to 1.93, p=0.992) were similar between the MeVO and LVO groups after adjusting for the confounders. We identified that baseline neutrophil-to-lymphocyte ratio ≤4.1 (OR=2.13, 95% CI 1.14 to 3.99, p=0.019), baseline National Institutes of Health Stroke Scale ≤14 (OR=1.96, 95% CI 1.02 to 3.80, p=0.045) and mechanical thrombectomy passes ≤1 (OR=2.16, 95% CI 1.14 to 4.11, p=0.021) were independent predictors of the 90-day good outcome in MeVO patients undergoing EVT.

CONCLUSIONS

Patients with MeVO achieved similar 90-day mRS, SICH rate and successful recanalisation rate after EVT compared with patients with LVO. Several independent predictors of 90-day good outcome in MeVO patients undergoing EVT were determined, which should be highly considered in MeVO stroke management.

Mechanical Thrombectomy for M2 Segment Occlusion in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

The safety and benefit of mechanical thrombectomy (MT) in the treatment of acute ischemic stroke (AIS) patients with M2 segment middle cerebral artery occlusions remain uncertain.

OBJECTIVE

To investigate the benefit of mechanical thrombectomy for M2 occlusion compared with M1 occlusion in patients with AIS.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched from inception to April 2021 to identify relevant articles. The main results comprised 90-day functional independence (modified Rankin Score from 0-2), successful recanalization (thrombectomy in cerebral infarction [TICI] 2b/3), mortality, and rates of symptomatic intracerebral hemorrhage after using modern thrombectomy devices. Odds ratios (ORs) were generated for binary variants. ReviewManager 5.3 software was used.

RESULTS

Ultimately, a total of 14 trials were included, with 3454 participants enrolled. MT for M2 occlusion had a higher rate of 3-month functional independence than M1 occlusion, but the difference was nonsignificant (OR: 1.19, 95% confidence interval [CI]: 0.98 to 1.46). The TICI2b/3 scores (OR: 0.71, 95% CI: 0.58-0.88) in M2 occlusion were remarkably lower than those in M1. The mortality and symptomatic intracerebral hemorrhage rates were comparable between the 2 groups. When comparing M2 and M1 occlusions, we found that there was no significant difference between stent retriever and aspiration in the modified Rankin Score (0-2) after AIS, but aspiration exerted an eminently higher recanalization rate with regard to TICI2b/3 (OR: 0.77, 95% CI: 0.61-0.96).

CONCLUSIONS

Compared with M1 occlusion, patients with M2 occlusion treated by MT demonstrated similar clinical outcomes in this study. Moreover, there was no difference between stent retriever and aspiration in treating M2 occlusion in terms of functional independence at 90 days. However, aspiration exerted a conspicuously higher recanalization rate in M2 occlusion than in M1 occlusion.

Association of CT-Based Hypoperfusion Index With Ischemic Core Enlargement in Patients With Medium and Large Vessel Stroke

BACKGROUND AND OBJECTIVES

The rate of infarct core progression in patients with acute ischemic stroke is variable and affects outcome of reperfusion therapy. We evaluated the hypoperfusion index (HI) to estimate the initial rate of core progression in patients with medium vessel occlusion (MeVO) compared to large vessel occlusion (LVO) stroke and within a larger time frame since stroke onset.

METHODS

Core progression was assessed in 106 patients with acute stroke and CT perfusion. Using reperfusion trial core time criteria, fast progressors had core >70 mL within 6 hours of stroke onset and slow progressors had core ≤70 mL, mismatch ≥15 mL, and mismatch to core ratio ≥1.8 within 6 to 24 hours. The relationship between HI and infarct core progression (core/time) was examined using receiver operating characteristics to determine optimal HI cutoff. The HI cutoff was then tested in the overall cohort, compared between MeVO and LVO, and evaluated in patients up to 24 hours from stroke onset to differentiate fast from slow rate of core progression. HI threshold was assessed in a second independent cohort of 110 patients with acute ischemic stroke.

RESULTS

In 106 patients with acute stroke, 6.6% were fast progressors, 27.4% were slow progressors, and 66% were not classified as fast or slow progressor by reperfusion trial core time criteria. HI >0.5 was associated with fast progression and able to distinguish fast from slow progressors (area under the curve [AUC] 0.94; 95% confidence interval [CI] 0.80-0.99). In MeVO (n = 26) HI >0.5 had a core progression of 0.30 mL/min compared to 0.03 mL/min for HI ≤0.5 (p < 0.001). In LVO (n = 80), HI >0.5 had a core progression of 0.26 mL/min compared to 0.02 mL/min for HI ≤0.5 (p < 0.001). In patients not classified as fast or slow progressor by reperfusion trial criteria, those with HI >0.5 had progression rate of 0.21 mL/min compared to 0.03 mL/min for those with HI ≤0.5 (p < 0.001). Validation in a second cohort of patients with acute ischemic stroke (n = 110; MeVO = 42, LVO = 68) yielded similar results for HI >0.5 to distinguish fast and slow core progression with an AUC of 0.84 (95% CI 0.72-0.97).

DISCUSSION

HI can differentiate fast from slow core progression in MeVO and LVO within the first 24 hours of acute ischemic stroke. Consideration of core progression rate at time of stroke evaluation may have implications in the selection of patients with MeVO and LVO stroke for reperfusion therapy that warrant further study.

Mechanical thrombectomy for acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery: A literature review

Thanks to new generation devices, mechanical thrombectomy (MT) has substantially evolved and become the standard treatment for patients with acute occlusion of the internal carotid artery or proximal middle cerebral artery (MCA) (M1 segment). However, the role and benefit of MT in patients with distal MCA (M2 segment) occlusion remain unclear. Therefore, there is a need for further studies. To evaluate the efficacy and safety of MT for M2 occlusion, this article reviews the natural course of M2 occlusion, the evidence regarding MT for M2 segment occlusion, clinical outcomes of MT for M2 occlusion, and treatment outcomes according to device type.

Reasons for Not Performing Mechanical Thrombectomy: A Population-Based Study of Stroke Codes

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Endovascular reperfusion of M2 occlusions in acute ischemic stroke reduced disability and mortality: ETIS Registry results

BACKGROUND

The predictors of successful reperfusion and the effect of reperfusion after endovascular treatment (EVT) for M2 occlusions have not been well studied. We aimed to identify predictors of successful reperfusion and the effect of reperfusion on outcomes of EVT for M2 occlusions in current practice.

METHODS

Patients with acute ischemic stroke due to isolated M2 occlusions who were enrolled in the prospective multicenter Endovascular Treatment in Ischemic Stroke (ETIS) Registry in France between January 2015 and March 2020 were included. The primary outcome was a favorable outcome, defined as modified Rankin Scale (mRS) score of 0-2 at 90 days. Successful reperfusion was defined as an improvement of ≥1 points in the modified Thrombolysis In Cerebral Infarction score between the first and the last intracranial angiogram.

RESULTS

A total of 458 patients were included (median National Institutes of Health Stroke Scale (NIHSS) score 14; 61.4% received prior intravenous thrombolysis). Compared with the non-reperfused patients, reperfused patients had an increased rate of excellent outcome (OR 2.3, 95% CI 0.98 to 5.36; p=0.053), favorable outcome (OR 2.79, 95% CI 1.31 to 5.93; p=0.007), and reduced 90-day mortality (OR 0.39, 95% CI 0.19 to 0.79; p<0.01). Admission NIHSS score was the only predictor of successful reperfusion. First-line strategy was not a predictor of successful reperfusion or favorable outcome, but the use of a stent retriever, alone or with an aspiration catheter, was associated with higher rates of procedural complications and 90-day mortality.

CONCLUSIONS

Successful reperfusion of M2 occlusions reduced disability and mortality. However, safety is a concern, especially if the procedure failed.

Effectiveness and safety of endovascular thrombectomy for large versus medium vessel occlusions: a single-center experience

BACKGROUND

The effectiveness and safety of endovascular thrombectomy (EVT) for medium vessel occlusions (MeVO) in the anterior intracranial circulation for patients with acute ischemic stroke (AIS) has yet to be definitively established. We compared outcomes in patients undergoing EVT for large vessel occlusion (LVO) versus those with MeVO.

METHODS

This retrospective cohort study, using an intention to treat design, compared the 90-day modified Rankin Scale (mRS) score between 43 patients with MeVO and 199 with LVO in the anterior intracranial circulation. Secondary outcome measures included vessel recanalization using the Thrombolysis in Cerebral Infarction (TICI) score, procedural complications, post-EVT intracranial hemorrhage (ICH), and infarct size.

RESULTS

The rate of good functional outcome (90-day mRS 0-2) was higher in patients with LVO than in those with MeVO (32.9% vs 27%), but this was not statistically significant (p=0.19). The rate of EVT procedural complications was also not significantly different between the groups (p=0.10), nor was the rate of ICH (p=0.30). There was also no significant difference in TICI scores between groups (p=0.12). Infarct size was larger in the LVO group (p<0.01). Multivariate analysis showed older age, not receiving recombinant tissue plasminogen activator (r-tPA), and larger infarct size were independent predictors of poor functional outcome at 90 days.

CONCLUSION

The 90-day mRS and rate of periprocedural complications were not significantly different between patients treated for LVO and those treated for MeVO with EVT. Older age, not receiving r-tPA, and larger infarct size were independent predictors of poor outcome at 90 days.

Mechanical thrombectomy of acute distal posterior cerebral artery occlusions

To describe our experience with mechanical thrombectomy (MTE) of acute distal posterior cerebral artery (PCA) occlusions, either isolated or in combination with more proximal vessel occlusions regarding recanalization rates, MTE techniques, and procedural safety. From the prospectively maintained stroke thrombectomy databases of two institutions, all consecutive patients subjected to MTE of acute distal PCA occlusion (P2 and 3 segments) between July 2013 and May 2020 were retrospectively identified. Imaging data and angiographic features, as well as patients' demographic and clinical data were evaluated. 35 consecutive patients were included in the study. In 17 patients MTE of isolated acute distal PCA occlusion was performed. 9 patients had combined basilar artery (BA) and distal PCA occlusion on stroke imaging and 3 had embolic distal PCA occlusion following MTE for BA occlusion. 6 patients harbored distal PCA occlusions in combination with carotid-T occlusion and a dominant posterior communicating artery. The median NIHSS at presentation was 14 (IQR 8 - 27). 25 patients (71.4%) had occlusions of the P2 and 10 patients (28.6%) of the P3 segment. Successful recanalization (TICI 2b/3) was achieved in 31 patients (88.6%). 10 patients (28.6%) were treated with a direct contact aspiration technique, while a stent retriever was used in 25 patients (71.4%). No complication attributable to distal PCA MTE occurred. Good outcome (mRS ≤ 2) was achieved in 14 patients (46.7%) and mortality was 22.9%. MTE for acute distal PCA occlusion in the setting of different occlusion patterns appears both safe and angiographically effective. Yet, clinical effectiveness remains to be determined.

Thrombectomy for Small-Artery Occlusions with the Small-Diameter Stent Retriever, Tron Fx 2 mm × 15 mm: A Case Series

Objective

The safety and efficacy of thrombectomy for small-artery occlusions is still controversial. In April 2019, Tron Fx, a stent retriever with an expansion diameter of 2 mm, became reimbursed by health insurance in Japan. We report on cases of thrombectomy for small-artery occlusions performed using this device in seven patients.

Methods

The subjects were seven patients who underwent thrombectomy between July 2019 and June 2020 using Tron Fx with 2 mm in diameter. We analyzed clinical results including recanalization and complications.

Results

The mean age of the seven patients was 80.1 years, and the subjects included six men. The sites of occlusion were the middle cerebral artery M2 (n = 4), M4 (n = 1), anterior cerebral artery A2 (n = 1), and A3 (n = 1). One of the seven patients had an M2 occlusion that was formed during coil embolization for a ruptured cerebral aneurysm. In five cases, four cases were of primary occlusion and one case was of emboli into a new territory, treating with only Tron Fx 2 mm resulted in thrombolysis in cerebral infarction (TICI) 2b-3 in four cases. There was one case of grade 0, which was M4 occlusion. Finally, TICI 2b-3 were achieved in six of seven cases. No symptomatic intracranial hemorrhage occurred. Symptoms improved in five of six patients, excluding a vascular occlusion that occurred during surgery.

Conclusion

Tron Fx with 2 mm diameter can be used safely for small-artery occlusion. The introduction of Tron Fx with 2 mm diameter may contribute to expand indications for thrombectomy for small-artery occlusions.

Results of Mechanical Thrombectomy 6 Hours after Stroke Onset: Analysis of Multiple Stroke Centers in Fukushima Prefecture

Objective

The purpose of this study was to examine the efficacy and safety of mechanical thrombectomy in patients with acute occlusion of a large cerebral artery in the anterior circulation beyond 6 hours of the time last known to be well using the real-world clinical data collected from non-urban areas of Japan.

Methods

We analyzed a retrospective multicenter database collected at 10 thrombectomy capable primary stroke centers in Fukushima Prefecture. In all, 188 patients were presenting a large cerebral artery occlusion in the anterior circulation, that is, internal carotid and middle cerebral artery (M1 and M2 segment). In all, 158 patients received mechanical thrombectomy within 6 hours from symptom onset (early time window), and 30 patients exceeded 6 hours (late time window). We compared the patient background, outcomes, and safety variables between the two groups. The modified Rankin Scale (mRS) score of 0-2 at 90 days after treatment and the incidence of symptomatic intracranial hemorrhage were compared between groups to evaluate treatment efficacy and safety.

Results

There was no significant difference in the proportion of mRS score 0-2 at 90 days after treatment (51.3 vs. 46.7%: P = 0.644). However, symptomatic intracranial hemorrhage was more frequent in the late time window group (7.0 vs. 16.7%: P = 0.081). Symptomatic intracranial hemorrhage was a significant factor of a poor functional outcome in the late time window group (P = 0.022).

Conclusion

This study reflects the real-world results of mechanical thrombectomy in the non-urban areas of Japan. The treatment efficacy in the late time window patients was equivalent to that in the early time window patients. On the other hand, the incidence of symptomatic intracranial hemorrhage showed a trend to high in patients beyond 6 hours, which was a significant factor related to a poor functional outcome.

Microcatheter infusion of bolus-dose tirofiban for acute ischemic stroke due to distal intracranial artery occlusion

The utility of endovascular thrombectomy for acute occlusion of the distal intracranial artery (A2/A3/M2/M3/P2/P3) is unclear, and aspiration and stent thrombectomy are associated with risk of bleeding. We analyzed patients with acute occlusion of the distal intracranial artery to assess the safety and efficacy of microcatheter-based tirofiban infusion.We retrospectively reviewed data of the endovascular thrombectomy registry of our center between January 2018 and June 2019. Patients with distal intracranial artery occlusion who underwent endovascular thrombectomy with microcatheter-based infusion of tirofiban were recruited.Of 13 patients included, 1 presented with anterior cerebral artery occlusion, 2 with posterior cerebral artery occlusion, 2 with posterior inferior cerebellar artery occlusion, and 7 with middle cerebral artery M2 occlusion. The mean National Institute of Health Stroke scale score was 10.1 (3-19). Three patients (23.1%) underwent bridging treatment of intravenous thrombolysis with recombinant plasminogen activator and endovascular thrombectomy. The arithmetic mean onset-to-recanalization time was 696.3 minutes (140-1440) and average operating time was 47.1 minutes (30-80). After treatment, 10 patients (76.9%) underwent revascularization. No operative complications were observed in any case. All patients underwent angiography and were reviewed 7 to 14 days after surgery. Imaging revealed significant improvements in recanalization compared with the immediate postoperative period, with no reoccurrence of occlusion. The mean modified Rankin scale score at the 3-month follow-up was 0.54 (0-2).Microcatheter-based infusion of bolus-dose tirofiban can result in safe and effective recanalization of acute occlusion of the distal artery in the case of a relatively light thrombotic load.

Increased Rate of Successful First Passage Recanalization During Mechanical Thrombectomy for M2 Occlusion

BACKGROUND

Mechanical thrombectomy (MT) is the standard of care for the treatment of acute ischemic stroke (AIS) caused by anterior circulation large-vessel occlusion. However, the true safety and efficacy of MT in medium-size vessel occlusions such as the M2 segment of the middle cerebral artery have yet to be completely defined. In this study, we analyze the safety and efficacy of MT in M2 occlusions compared with M1 occlusions.

METHODS

A retrospective analysis was performed of patients with AIS secondary to M1 and M2 occlusions between 2011 and 2018. The inclusion criteria were 1) AIS secondary to M1 or M2 occlusion, 2) MT performed by stentrieval technique alone, aspiration technique, or combined stentrieval-aspiration techniques. Basic patient characteristics, number of passages, first passage recanalization success (≥TICI [Thrombolysis in Cerebral Ischemia] grade 2b), total recanalization success, hemorrhagic complications (including intracerebral hemorrhage [ICH] and subarachnoid hemorrhage), and clinical outcomes were compared between both groups.

RESULTS

Two hundred and sixty patients met the inclusion criteria; 171 patients had M1 occlusion versus 89 with M2 occlusion. First passage recanalization success rate was significantly higher in the M2 group (55.1% vs. 39.2%; P = 0.015). Total recanalization success rate was higher in the M2 group but did not reach significance (83% vs. 75%; P = 0.128). Subarachnoid hemorrhage rate was significantly higher in the M2 group (25% vs. 12%; P = 0.010) but there was no difference for ICH complications (14.6% vs. 16.4%; P = 0.711).

CONCLUSIONS

MT for M2 occlusions has similar overall efficacy to that for M1 occlusions, but with higher first-pass successful recanalization rates. MT for M2 occlusions has a higher risk of associated subarachnoid hemorrhage.

Current Status of Treatment for Acute Large Vessel Occlusion Stroke in Awaji Island Area after the Introduction of Endovascular Treatment

Objective

We retrospectively analyzed the current status of treatment for anterior circulation large vessel occlusion (LVO) in island areas with a high population aging rate.

Methods

We investigated 62 consecutive patients with ischemic stroke due to acute anterior circulation LVO between October 1, 2017 and June 30, 2019.

Results

In all, 26 (41.1%) patients underwent endovascular treatment (EVT). The successful recanalization rate of EVT was 88.5% (23/26). There was a significant difference in the age (median, 75.5 years vs. 81 years, respectively, P = 0.0411) and the rate of intravenous tissue plasminogen activator (tPA) therapy (53.5% vs. 11.1%, respectively, P <0.001) between the EVT group and the non-EVT group. Patients in the EVT group achieved a favorable outcome more frequently than those in the non-EVT group (50% vs. 11.1%, respectively, P = 0.0012). In the analysis based on the place of onset among the three cities comprising Awaji Island and the four groups with in-hospital onset, there was no significant difference in the rate of EVT, and the outcome of the in-hospital onset group was poor. Among the EVT group, there was a significant difference in the pre-treatment National Institutes of Health Stroke Scale score (median, 15 vs. 19, respectively, P = 0.0237) and time from onset to recanalization (O2R; median, 240 min vs. 323 min, respectively, P = 0.0128) between the favorable outcome group and the unfavorable outcome group.

Conclusion

Even in an island area, it is possible to complete the treatment of ischemic stroke due to LVO within the regional medical area.

Endovascular Treatment Decisions in Patients with M2 Segment MCA Occlusions

BACKGROUND AND PURPOSE

Endovascular therapy in acute ischemic stroke is rapidly evolving. We explored physicians' treatment attitudes and practice in patients with acute ischemic stroke due to M2 occlusion, given the absence of Level-1 guidelines.

MATERIALS AND METHODS

We conducted an international multidisciplinary survey among physicians involved in acute stroke care. Respondents were presented with 10 of 22 case scenarios (4 with proximal M2 occlusions and 1 with a small-branch M2 occlusion) and asked about their treatment approach under A) current local resources, and B) assumed ideal conditions (no monetary or infrastructural restraints). Overall treatment decisions were evaluated; subgroup analyses by physician and patient baseline characteristics were performed.

RESULTS

A total of 607 physicians participated. Most of the respondents decided in favor of endovascular therapy in M2 occlusions, both under current local resources and assumed ideal conditions (65.4% versus 69.6%; P = .017). Under current local resources, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P < .001), high personal endovascular therapy volume (P = .005), and neurosurgeons (P < .001) were more likely to favor endovascular therapy. European respondents were less likely to favor endovascular therapy (P = .001). Under assumed ideal conditions, older patient age (P < .001), longer time since symptom onset (P < .001), high center endovascular therapy volume (P = .041), high personal endovascular therapy volume (P = .002), and Asian respondents were more likely to favor endovascular therapy (P = .037). Respondents with more experience (P = .048) and high annual stroke thrombolysis treatment volume (P = .001) were less likely to favor endovascular therapy.

CONCLUSIONS

Patients with M2 occlusions are considered appropriate candidates for endovascular therapy by most respondents in this survey, especially by those performing endovascular therapy more often and those practicing in high-volume centers.

Efficacy and safety of mechanical thrombectomy for M2 segment of middle cerebral artery: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

The efficacy and safety of mechanical thrombectomy (MT) for M2 segment occlusion of middle cerebral artery in patients with acute ischemic stroke (AIS) was investigated.

METHODS

We searched PubMed and EMBASE from inception to 16 April 2019 for relevant studies, calculated the pool relative risks (RRs) of 3-month functional independence (modified Rankin scale score 0-2), death and symptomatic intracerebral hemorrhage (sICH) in MT for M2 segment occlusion in patients with AIS versus those of M1 segment or best medical care.

RESULTS

Nine studies enrolling 2152 patients compared MT for patients with AIS of M2 segment occlusion and those of M1 segment occlusion. MT for M2 occlusion had a higher rate of 3-month functional independence compared to the patients with M1 occlusion. (RR 1.27, 95% CI 1.11-1.44, P < 0.001) and decreased death (RR 0.74; 95% CI 0.58-0.96, P = 0.022) with similar risk of sICH (RR 1.11; 95% CI 0.65-1.87, P = 0.707). Four studies enrolling 1016 patients compared MT and best medical care for patients with AIS of M2 occlusion. MT for M2 occlusion benefit more than best medical care on 3-month functional independence (RR 1.43, 95% CI 1.08-1.90, P = 0.011) and death (RR 0.46; 95% CI 0.22-0.96, P = 0.022) with similar risk of sICH (RR 1.65; 95% CI 0.66-4.13; P = 0.286).

CONCLUSION

MT for M2 segment benefit patients with AIS on 3-month functional independence compared with that of M1 segment or medical care, without increasing the risk of sICH.

ADAPT technique in ischemic stroke treatment of M2 middle cerebral artery occlusions in comparison to M1 occlusions: Post hoc analysis of the PROMISE study

Background/purpose

The benefit of endovascular thrombectomy in acute ischemic stroke (AIS) therapy of proximal large vessel occlusions (LVO) is established. However, there are few prospective studies evaluating the use of a direct aspiration first pass technique in distal vessel occlusions. This post hoc analysis of the PROMISE study examines the safety and effectiveness of the Penumbra System with the ACE68 and ACE64 Reperfusion Catheters for aspiration thrombectomy in the M1 and M2 segments of the middle cerebral artery.

Methods

PROMISE is a prospective, multicenter study that enrolled 204 patients with anterior circulation LVO AIS-treated frontline with ACE68/ACE64 catheters. We compared clinical and angiographic outcomes, complications, and mortality in patients with M1 and M2 occlusions. The association of M1 and M2 location and functional independence or mTICI 2b-3 reperfusion was described in univariable and multivariable analyses.

Results

One hundred sixty-one patients (124 M1 and 37 M2 locations) met the study criteria. Post procedure mTICI 2b-3 reperfusion (93% vs. 92%, p = 1.00), functional independence (57% vs. 70%, p = 0.18), symptomatic intracranial hemorrhage (1.6% vs. 2.7%, p = 0.55), device- or procedure-related serious adverse events at 30 days (4.0% vs. 8.1%, p = 0.39), and mortality at 90 days (6.6% vs. 2.7%, p = 0.69) were comparable between M1 and M2 occlusions. In multivariable analysis, lower age, lower baseline NIHSS, and shorter time from onset to admission were independent predictors of functional independence.

Conclusions

For frontline aspiration thrombectomy of stroke, use of large-bore ACE68/ACE64 catheters for treatment of M2 occlusions appeared as safe and effective as for M1 occlusions.

Mechanical Thrombectomy of the Middle Cerebral Artery - Neither Segment nor Diameter Matter

OBJECTIVES

The aim of this study was to explore the role of the vessel diameter at the site of middle cerebral artery (MCA) occlusion in acute ischemic stroke patients who underwent mechanical thrombectomy (MT) regarding technical aspects, safety, and clinical outcomes.

METHODS

In a retrospective analysis, cerebral artery diameters were measured using digital subtraction angiography in patients with isolated M1 or M2 occlusions undergoing MT. Associations between occluded vessel, occlusion diameter and outcomes were analyzed using logistic regression models adjusting for prespecified prognostic factors.

RESULTS

168 patients with M1 occlusions and 98 patients with M2 occlusions who underwent MT were included. Mean vessel diameters at M1 and M2 occlusion sites differed significantly (2.15 +/- .36 1.55 +/- .38, P < .001). Vessel diameters at the occlusion site and occluded vessel segment did not predict good functional outcome (aOR 1.2 CI .28-5.26, P = .659; aOR .84 CI .35-2.03, P = .841) or mortality (aOR .21 CI .04-1.01, P = .215; aOR 1.36 CI .55-3.37, P = .676). No significant differences in successful recanalization, good functional outcome, mortality, procedural complications, and intracranial hemorrhages between M1 and M2 occlusions was observed.

CONCLUSIONS

In this study no significant effect of the MCA vessel diameter on successful recanalization, good functional outcome, or mortality of acute ischemic stroke patients treated with MT could be detected. However, these findings need to be confirmed in further studies.

Mechanical thrombectomy with second-generation devices for acute cerebral middle artery M2 segment occlusion: A meta-analysis

BACKGROUND

The benefit of mechanical thrombectomy for an acute ischemic stroke involving M2 segment occlusion is not clear, especially when performed with second-generation thrombectomy devices.

METHOD

We reviewed the literature to investigate clinical outcomes and the rates of recanalization, symptomatic intracerebral hematoma, and mortality in mechanical thrombectomy performed using second-generation thrombectomy devices. We compared the outcomes between patients treated for M2 and M1 occlusions.

RESULTS

Seven studies involving 805 patients with M2 thrombectomy were included in this meta-analysis. The functional independence rate 90 days after thrombectomy (modified Rankin Scale 0-2) was 59.3% (OR 1.81, 95% CI 1.74-1.88). The recanalization rate (thrombolysis in cerebral infarction 0-2) was 84.16% (OR 2.32, 95% CI 2.08-2.29). The symptomatic intracerebral hematoma rate was 4.9% (OR 1.05, 95% CI 1.03-1.09). The mortality was 7.7% (OR 1.08, 95% CI 1.03-1.13). The outcomes were better in patients with M2 occlusion than in those with M1 occlusion. In a subgroup analysis, we found that among patients with hypertension, mechanical thrombectomy achieved better functional outcomes and recanalization in M2 occlusion than M1 occlusion.

CONCLUSION

Mechanical thrombectomy performed with second-generation thrombectomy devices for M2 occlusion can provide a good functional outcome as well as satisfying recanalization. Moreover, there was no significant difference in the symptomatic intracerebral hematoma and mortality rates, suggesting this procedure is as safe in M2 occlusion as in M1 occlusion.

Mechanical Thrombectomy of Distal Occlusions Using a Direct Aspiration First Pass Technique Compared with New Generation of Mini-0.017 Microcatheter Compatible-Stent Retrievers: A Meta-Analysis

BACKGROUND

There are no current evidence-based recommendations on mechanical thrombectomy (MT) in M2 or other distal occlusions. The objective of this paper was to investigate clinical and radiologic outcomes of MT in distal locations using the new generation of mini-0.017 microcatheter compatible-stent retrievers (SRs) compared with a direct aspiration first pass technique (ADAPT) MT.

METHODS

A systematic search was performed for studies published from January 2016 to March 2019. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies that reported clinical and radiologic outcomes of patients undergoing MT using new generation of SRs or ADAPT in distal locations. The cumulative prevalence was estimated for each outcome. Heterogeneity of the data was assessed by the Higgins index (I²), and a random-effects model was applied.

RESULTS

Fifteen studies and 494 patients were included; 7 studies reported on patients treated with a new SR and 8 studies analyzed patients treated with ADAPT. The rate of thrombolysis in cerebral infarction score 2b-3 after MT for distal occlusions was 80.6% (383 of 494; 95% confidence interval [CI], 74.8%-86.3%; I² = 64.4%). Successful recanalization was comparable after SR use with low-profile devices and ADAPT (176 of 226; 82%; 95% CI, 72.6%-1.5%; I² = 70.5% vs. 207 of 268; 79.4%; 95% CI, 71.8%-86.9%; I² = 60.8%, respectively; P = 0.4). The rate of the modified Rankin scale score of 0-2 at 3 months was higher in the ADAPT group (160 of 251; 68.9%; 95% CI, 51.8%-85.9%; I² = 92.2%) than the SR group (92 of 177; 58.7%; 95% CI, 37.3%-80%; I² = 58.7%; P = 0.01). The mortality rate was lower among the ADAPT group (20 of 251; 5.4%; 95% CI, 1.4%-9%; I² = 63%) than the SR group (16 of 108; 13%; 95% CI, 6%-19%; I² = 13%; P = 0.008).

CONCLUSIONS

MT in distal locations using the new generation of SR yields comparable results compared with ADAPT in terms of recanalization; however, the use of SR is associated with lower functional independence and higher mortality rate.

Mechanical thrombectomy for recurrent large vessel occlusion

Although mechanical thrombectomy (MT) has been shown in numerous trials to be a successful treatment option for patients with large vessel occlusion (LVO), there is limited information on the safety and effectiveness of the technique in cases of recurrent LVO. To this end, we performed a retrospective review of our prospectively maintained database to identify all patients that had undergone more than one MT procedure January 2008 and January 2018. The data collected on these patients included baseline demographics and any history of diabetes mellitus, hypercholesterolaemia, hypertension, atrial fibrillation or smoking. We also recorded when the symptoms had started, the patient's NIHSS and ASPECT scores, the number of passes taken, the patient's final TICI score, any complications which arose and the patient's mRS at 90 days. Our dataset encompassed 25 patients (of which 17 (68%) were female) who had undergone a total number of 52 MT's. Average age at 1st presentation was 70 ± 12.8 years. The median time between one stroke and the next was 71 days (range 1-1059, IQR 183 days). The majority of the strokes were deemed cardioembolic (86.5%) in origin. There was no significant difference in the procedure times, number of passes or TICI scores. There was a significant difference in the mRS after the 1st and 2nd events (p = 0.014) but no significant difference if the 2nd event occurred contralateral to the 1st event (p = 0.66) (n = 22). It is therefore concluded that recurrent thrombectomy can be safely performed with no significant difference in the technical aspects of the procedure.

Thrombectomy for M2 occlusions and the role of the dominant branch

INTRODUCTION

The benefits of thrombectomy for occlusion of M2 segments remain controversial. The aim of this study is to assess thrombectomy's efficacy and safety in patients with M2 segment occlusion and associations between occlusion sites and anatomic variations of M1 division.

MATERIALS AND METHODS

A prospective series of 30 patients with acute ischemic stroke (AIS) resulting from M2 segment occlusion of the middle cerebral artery (MCA) who underwent thrombectomy was analyzed. The primary endpoint was assessed by the Extended Treatment in Cerebral Infarction scale (eTICI). The secondary endpoints were the incidence of symptomatic hemorrhagic transformation (sICH), mortality and good functional outcome at three months.

RESULTS

The mean patient age was 69.2 years. The mean National Institutes Health Stroke Scale score (NIHSS) upon hospital admission was 16. The recanalization rates were eTICI 2b/3 in 90% and 2c/3 in 60% of the patients. Total recanalization of the M2 branch was achieved in 53% of patients. sICH incidence was 6.6%, the mortality rate was 30%, and a good functional outcome (mRS ≤2) was observed in 50% of the patients. Twenty-seven patients (90%) had a dominant M2 branch and all were occluded. Regarding the site of M2 occlusions, 74% of patients had proximal M2 occlusions.

CONCLUSIONS

Thrombectomy appears to be a safe and effective method for the treatment of acute M2 segment occlusions of the MCA. Most of the cases had a dominant M2 branch, and all of them were occluded. Larger studies are needed to verify the benefits of thrombectomy for different settings of M2 occlusions.

Meta-Analysis of Endovascular Treatment for Acute M2 Occlusion

Objective

Endovascular treatment (EVT) outcomes for acute M2 segment of middle cerebral artery occlusion remains unclear because most results are obtained from patients with large artery occlusion in the anterior circulation. The objective of this study was to assess procedural outcomes for acute M2 occlusion and compare outcomes according to thrombus location (M1 vs. M2).

Methods

A systematic review was performed for online literature published from January 2004 to December 2016. Primary outcome was successful recanalization rate and symptomatic intracranial hemorrhage (S-ICH) after the procedure. A fixed effect model was used if heterogeneity was less than 50%.

Results

Eight articles were included. EVT showed successful recanalization rate of 69.1% (95% confidence interval [CI], 54.9–80.4%) and S-ICH rate of 6.1% (95% CI, 4.5–8.3%). The rates of good clinical outcome at 3 months and mortality were 59.4% (95% CI, 49.9–68.2%) and 14.9% (95% CI, 11.4–19.3%), respectively. According to thrombus location (M1 vs. M2), successful recanalization (odds ratio [OR], 1.539; 95% CI, 0.293–8.092; p=0.610) and S-ICH (OR, 1.313; 95% CI, 0.603–2.861; p=0.493) did not differ significantly. Good clinical outcome was more evident in M2 occlusion after EVT than that in M1 occlusion (OR, 1.639; 95% CI, 1.135–2.368; p=0.008). However, mortality did not differ significantly according to thrombus location (OR, 0.788; 95% CI, 0.486–1.276; p=0.332).

Conclusion

EVT seems to be technically feasible for acute M2 occlusion. Direct comparative studies between EVT and medical treatment are needed further to find specific beneficiary group after EVT in patient with M2 occlusion.

Endovascular Treatment: The Role of Dominant Caliber M2 Segment Occlusion in Ischemic Stroke

Background and Purpose- It is unclear whether endovascular treatment (EVT) is beneficial for patients with acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery. We aimed to compare functional outcomes, technical aspects, and complications of EVT between patients with acute ischemic stroke because of M2 and M1 occlusions in clinical practice. Furthermore, outcome and complications after EVT in dominant and nondominant caliber M2 division occlusions were studied. Methods- Data were obtained from the MR CLEAN Registry (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) which is an ongoing observational study in 16 Dutch centers performing EVT in the Netherlands. Functional outcome was measured with the modified Rankin Scale score at 90 days. Neurological recovery (delta National Institutes of Health Stroke Scale), successful reperfusion rates (extended Thrombolysis in Cerebral Infarction ≥2B), and safety outcomes were also investigated. Associations between occlusion location and outcome were analyzed with ordinal logistic regression models, with adjustment for other prognostic factors. Results- In total, 244 (24%) patients with an M2 and 759 (76%) patients with an M1 occlusion who underwent EVT were analyzed. Functional outcomes were not significantly different between patients with M2 versus M1 occlusions (adjusted common odds ratio, 1.24; 95% CI, 0.87-1.73). Occurrence of symptomatic intracerebral hemorrhage was also similar for M2 and M1 occlusions (6.6% versus 5.9%; P=0.84). Further analysis about dominance of an M2 branch was performed in 175 (72%) patients. Neurological recovery was comparable (mean delta National Institutes of Health Stroke Scale, -2±10 for dominant M2, -5±5 for nondominant M2, and -4±9 [ P=0.24] for M1 occlusions). Furthermore, the effect of reperfusion status on functional outcome was comparable between occlusion divisions (common odds ratio, 1.27; 95% CI, 1.06-1.53 for dominant M2; common odds ratio, 1.32; 95% CI, 0.93-1.87 for nondominant M2; and common odds ratio, 1.35; 95% CI, 1.24-1.46 for M1 occlusions). Conclusions- Outcomes and complication rates after EVT were similar in patients with M2 and M1 occlusions. Although based on observational data and a limited sample size, a similar association of reperfusion status with functional outcome for all subgroups provides no evidence that patients with either a dominant or a nondominant M2 occlusion should be routinely excluded from EVT.

Contact Aspiration versus Stent-Retriever Thrombectomy for Distal Middle Cerebral Artery Occlusions in Acute Ischemic Stroke: Meta-Analysis

PURPOSE

The evidence for endovascular therapy and choice of technique in distal middle cerebral artery (MCA) M2 segment occlusions in acute ischemic stroke remains controversial. We aimed to conduct a systematic review and meta-analysis primarily comparing reperfusion rates of stent-retrieval versus contact aspiration for M2 occlusions.

MATERIALS AND METHODS

Study selection included cohorts of patients with distal MCA occlusions in acute ischemic strokes treated with an endovascular approach including stent-retrieval or contact aspiration. Twelve studies were selected for meta-analysis for a total of 835 cases. Meta-analysis by proportions was conducted on parameters including baseline and procedural characteristics, thrombolysis in cerebral infarction (TICI) 2b-3 outcomes, and 90-day modified Rankin scale (mRS) outcomes.

RESULTS

Hypertension and hyperlipidemia were more prevalent in stent-retriever patients. Pooled baseline National Institute of Health Stroke Scale scores and Alberta Stroke Program Early Computed Tomography Score imaging scores were similar. Pooled time onset of symptoms to door arrival was higher for the stent-retrieval group (154 vs. 97.4 minutes, P=0.01), as was time to groin puncture (259.9 vs. 156.2 minutes, P=0.02), but there was no difference in procedure time. The TICI 2b-3 recanalization rate was similar (80.5% vs. 86.8%, P=0.168). The frequency of mRS 0-2 at 90-day was also similar (74.5% vs. 59.9%, P=0.120), and an excellent mRS 0-1 was lower for stent-retrievers (39.9% vs. 65.6%, P=0.003). A significant negative correlation was found between onset to groin puncture time and the proportion of patients with a good mRS (r=-0.71, P=0.048).

CONCLUSION

Both endovascular techniques achieved recanalization rates greater than 80% and 90-day outcomes of minimal disability with similar complication rates. The literature is skewed by aspiration cases being performed sooner after onset of stroke compared to stent-retriever cases.

Introducing the New 3.5/28 Microstent Retriever for Recanalization of Distal Cerebral Arteries in Acute Stroke: Preliminary Results

BACKGROUND AND PURPOSE

To describe our first experience using a small stent retriever specifically designed for thrombectomy in cerebral arteries with a small caliber (Acandis APERIO^® 3.5/28) in patients with acute ischemic stroke.

MATERIALS AND METHODS

All patients with an acute ischemic stroke, who underwent endovascular recanalization using the APERIO^® thrombectomy device with a diameter of 3.5 mm, were identified in retrospect and included in the present analysis. Demographic and clinical data as well as data on the procedures performed were collected (patient sex, mean age, NIHSS, mRS, TICI score, and complications).

RESULTS

Stent retriever-based thrombectomy with the Aperio^® 3.5/28 alone (n = 10 vessels) or in combination with other devices (n = 13 vessels) was performed in 22 acute stroke patients with embolic occlusions of distal branches of the anterior and posterior circulations (median NIHSS = 8.5). For vessels treated with the Aperio^® 3.5/28, we achieved a TICI 2b/3 reperfusion rate of 73.9%. One patient suffered a symptomatic intracerebral hemorrhage after thrombectomy; otherwise, no procedure-related complications were seen.

CONCLUSION

Our data suggest that mechanical thrombectomy of distal cerebral artery occlusions with the Aperio^® 3.5/28 is feasible and in general safe, thus offering a promising option for endovascular stroke therapy. However, multicentric studies with larger patient cohorts are necessary to evaluate the clinical benefit.

Endovascular Retrieval of Migrated Coil within the Distal Middle Cerebral Artery Using Stentriever Device

BACKGROUND

Displacement of endovascular coils during endovascular embolization of an intracranial aneurysm is a potentially life-threatening complication. Several methods for coil retrieval have been described, including the use of microsnares and microforceps retrieval devices. With the recent surge of stentriever implementation in the treatment of ischemic stroke, some operators are now using such devices in the retrieval of migrated coils. We present a case of a balloon-assisted coil embolization of a communicating segment internal carotid artery aneurysm, complicated by coil migration far distally into the middle cerebral artery, which was retrieved successfully with a stentriever. To the best of our knowledge, this is the furthest migration of a coil to be successfully retrieved with a stentriever. We review conservative and invasive management of displaced coils and the technical advantages of stentrievers over retrieval devices.

METHODS

The patient's medical records were retrospectively reviewed, including clinical and radiographic information. This study received institutional review board approval.

RESULTS

The patient was treated with balloon-assisted coil embolization of the internal carotid artery aneurysm. The migrated coil was retrieved successfully using a novel application of a stentriever.

CONCLUSIONS

In certain situations, a stentriever does not mandate complete ensnaring of the target to be retrieved and thus need not always be deployed distal to a migrated coil mass to be successful. Due to the mechanical advantage of strut-engagement, stentrievers can afford to be positioned in relatively suboptimal positions, and this is especially useful in cases involving tortuous and small distal vessels (<2 mm diameter).

Mechanical Thrombectomy-A Brief Review of a Revolutionary new Treatment for Thromboembolic Stroke

The recent success of endovascular stroke treatment has heralded a new era in the management of acute ischemic stroke (AIS) with significantly improved outcome for patients. A large number of patients may be amenable to this new treatment and as the evidence expands the number of patients eligible for mechanical thrombectomy continues to increase. Recent evidence suggests that the time window for treatment can be extended up to 24 h after symptom onset for patients with anterior circulation strokes; however, many clinicians and medical professionals may not be aware of these recent changes and it is important that they are kept up-to-date with this rapidly evolving treatment. This review provides an overview of the recent successful trials and highlights important steps that should be instituted in order to achieve rapid reperfusion and optimize the outcome for ischemic stroke patients. It also looks at the remaining controversies facing the field of thrombectomy. A short summary of each of these contentious areas is provided and the current state of the art.

Mechanical thrombectomy for acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery: a meta-analysis

BACKGROUND

Endovascular thrombectomy has demonstrated benefit for patients with acute ischemic stroke from proximal large vessel occlusion. However, limited evidence is available from recent randomized trials on the role of thrombectomy for M2 segment occlusions of the middle cerebral artery (MCA).

METHODS

We conducted a systematic review and meta-analysis to investigate clinical and radiographic outcomes, rates of hemorrhagic complications, and mortality after M2 occlusion thrombectomy using modern devices, and compared these outcomes against patients with M1 occlusions. Recanalization was defined as Thrombolysis in Cerebral Infarction (TICI) 2b/3 or modified TICI 2b/3.

RESULTS

A total of 12 studies with 1080 patients with M2 thrombectomy were included in our analysis. Functional independence (modified Rankin Scale 0-2) rate was 59% (95% CI 54% to 64%). Mortality and symptomatic intracranial hemorrhage rates were 16% (95% CI 11% to 23%) and 10% (95% CI 6% to 16%), respectively. Recanalization rates were 81% (95% CI 79% to 84%), and were equally comparable for stent-retriever versus aspiration (OR 1.05; 95% CI 0.91 to 1.21). Successful M2 recanalization was associated with greater rates of favorable outcome (OR 4.22; 95% CI 1.96 to 9.1) compared with poor M2 recanalization (TICI 0-2a). There was no significant difference in recanalization rates for M2 versus M1 thrombectomy (OR 1.05; 95% CI 0.77 to 1.42).

CONCLUSIONS

This meta-analysis suggests that mechanical thrombectomy for M2 occlusions that can be safely accessed is associated with high functional independence and recanalization rates, but may be associated with an increased risk of hemorrhage.

Endovascular Stroke Treatment: How Far Downstream Should We Go?

BACKGROUND

Endovascular thrombectomy has become the de facto standard in the treatment of large vessel occlusion. Previously, a correlation between good outcome and the occlusion site, measured by the 'distance to thrombus' (DT)-as the distance from the carotid T to the beginning of the thrombus-after thrombolysis could be shown. In the present study, we analyze the differences between the chances of a good outcome in respect of DT between patients treated endovascularly or intravenously.

METHODS

A dual-center database analysis including patients with stroke due to occlusion of the middle cerebral artery (MCA) was performed. Inclusion criteria were a completed treatment and full documentation of the clinical course. DT was measured in pre-treatment images. DT was correlated with the mRS at 90 days stratified according to the different treatment methods.

RESULTS

A total of 280 patients could be included. We were able to show a correlation between the chances of good clinical outcome and the occlusion site measured by DT after i.v. thrombolysis. The outcome after endovascular treatment showed no correlation with DT (p = 0.227). After a DT of 26 mm, the chances of a good outcome after i.v. thrombolysis exceeded those after endovascular treatment.

CONCLUSION

In patients with MCA occlusion, the probability for a good outcome after endovascular treatment is independent of the occlusion site in contrast to the treatment with i.v. thrombolysis. If the occlusion occurred in the periphery of the M2 region (DT > 26 mm), i.v. thrombolysis alone was superior to endovascular treatment in achieving a good outcome.